I always put them on a sliding commission structure
They tell me during the appraisal 300k is the price they can get.
I say ok....
$300k and I will give you 1% Over $320k another .5% Over $340k another .5%
get me under 300k and I owe you nothing.
Its amazing how quickly they reduce the initial 300k estimate...lol
I signed with an agent once that I made him agree that for anything under 300k he pays me 1% of the non-sale price if nothing better comes in within 60 days.
Suffice to say it sold above and before the 60 days....and man he worked hard.